Apple trees

Question

Two years ago, one of my apple trees developed a strange illness then died that winter.
During late spring and summer a few of the leaf bunches at the ends of branches turned red/orange, then brown and died. It never spread to the whole tree, but that winter the tree went into hibernation then died over the winter. There is another apple tree of a different variety not more than 20 feet away that was not affected at all.
I have elected not to replace the dead tree, but this has been baffling me since. I lived in one of the northern suburbs cities around Dallas

Answer 1

It sounds like it was Cedar Apple Rust.

https://www.gardeningknowhow.com/edible/fruits/apples/apple-tree-diseases.htm
https://www.gardeningknowhow.com/edible/fruits/apples/cedar-apple-rust-control.htm

You may want to replace the dead tree to benefit your remaining tree, as a pollinator.
I would suggest checking with your local County Extension Office for a list of tree varieties known to thrive in your growing zone.
You can also check with local garden centers and greenhouses.

https://www.gardeningknowhow.com/extension-search/